NEWTOWN, Conn. (CBSNewYork) — An autism rights group this weekend urged people not to stigmatize those with the disorder in the wake of revelations that Newtown, Conn., elementary school gunman had Asperger’s syndrome.

A law enforcement official told the Associated Press that gunman Adam Lanza, 20, had been diagnosed with the high-functioning form of autism. The New York Times described him as socially awkward, and said he was known in high school as “intelligent, but nervous and fidgety, spitting his words out, as if having to speak up were painful.”

“He was really quiet. He kept to himself,” said Alex Israel, a high school classmate of Adam Lanza’s, speaking to “Piers Morgan Tonight.” “I mean he was a little fidgety, a little uneasy sometimes if you were just to look at him. I that he was just socially not really into going out there and making as many friends as everyone was really doing in elementary school and middle school. He preferred to stay to himself.”

“The search for answers should not be a search for a scapegoat. Autism is no excuse or explanation to evil. Being ‘autistic,’ ‘odd,’ ‘awkward,’ ‘camera shy,’ a ‘nerd’ and ‘uncomfortable with others’ does not cause a person to become a mass murderer,” the organization said in the release. “Autistic persons are more likely to be victims, rather than perpetrators of violence. Autism Rights Watch urges the public and the media outlets not to stigmatize the autistic persons and their families. They already are facing segregation and prejudices on a daily basis.”

Autism Rights Watch said “the easy access to weapons in our households” is the most significant factor to blame for the massacre at Sandy Hook Elementary School, which left 20 children and eight adults dead – including Lanza and his mother.

“We are very confident in the ability of the police and the President to address the root causes of this murder-suicide without resorting to scapegoats and hasty explanations,” the release said.

Lanza broke into the school using one of his weapons and opened fire on two classrooms. The Connecticut Chief Medical Examiner’s office said the 20 murdered children were all age 6 or 7 and each were shot multiple times.